1. Field of the Invention
The present invention relates to a method and system for the non-invasive measurement of health signs or prescribed characteristics of a subject.
2. Description of Related Art
Remote monitoring of prescribed characteristics of a subject, such as temperature, breathing and heart activity, can be useful for many applications where the knowledge of a subject's current medical condition or interactive responses is needed, but direct in-person interaction with, for example, a physician or monitoring system is not possible. This is particularly useful for outpatients with conditions that require vigilant observation. Monitoring such patients remotely can significantly reduce the cost and difficulty associated with frequent hospital visits.
Currently available outpatient monitoring systems involve the use of bulky and costly instruments that the patient or an assistant must apply and monitor in order to retrieve medical data. Thus, this procedure can only be performed at a fixed location (such as a doctor's office or the patient's home), when convenient. Some other types of smaller, more portable monitoring devices have been implemented for tracking and monitoring prescribed characteristics in various applications such as wildlife studies. These applications typically involve the attachment of an active electronic circuit to the subject, that can download recorded data, or transmit data to a remote receiver in realtime. Miniaturization and life span of these circuits is usually limited by the need for an internal battery, and telemetry of data usually requires that a transponder be administered to the device, or that the device radiate energy.
Accordingly, a demand exists for a more flexible monitoring system, which would allow the monitoring of subjects without undue restrictions on those subjects.